Evidence of climatic niche shift during biological invasion

TLDR

Niche‑based models calibrated in the native range using species observations and climatic variables are commonly used to predict invasion extent, assuming invasive species conserve their climatic niche in new ranges. The study tests whether Spotted Knapweed conserves its climatic niche by analysing its niche spaces in western North America and Europe. The authors analyse the climatic niche spaces of Spotted Knapweed in western North America and Europe to test niche conservation. Robust cross‑continental data show that Spotted Knapweed’s climatic niche shifted between native and non‑native ranges, and that niche‑matching models predict introduction sites but not full invasion extent, indicating that invasive species can occupy climatically distinct niches.

Abstract

Abstract Niche‐based models calibrated in the native range by relating species observations to climatic variables are commonly used to predict the potential spatial extent of species’ invasion. This climate matching approach relies on the assumption that invasive species conserve their climatic niche in the invaded ranges. We test this assumption by analysing the climatic niche spaces of Spotted Knapweed in western North America and Europe. We show with robust cross‐continental data that a shift of the observed climatic niche occurred between native and non‐native ranges, providing the first empirical evidence that an invasive species can occupy climatically distinct niche spaces following its introduction into a new area. The models fail to predict the current invaded distribution, but correctly predict areas of introduction. Climate matching is thus a useful approach to identify areas at risk of introduction and establishment of newly or not‐yet‐introduced neophytes, but may not predict the full extent of invasions.